Wednesday, June 25, 2008

Zero Defects

Agile concepts are not as new as you might think. In fact some concepts have been around for quite some time.

For instance look at Test-Driven Development (TDD). It is a technique that among other things uses prevention instead of inspection to achieve high quality code. And in all cases the objective must be zero known defect. It is not about "good enough" quality. What is "good enough" in this case? Is it 2 bugs, or 5, or 10? It doesn't really matter. "Good enough" is not specific enough when it comes to quality. Zero defects is the objective. That's specific. Is it achievable? Well, apparently sites like Flickr release new versions of their system up to every 30 minutes. Is this doable if you have low quality? Very unlikely. Without automated comprehensive, fast (= cheap) testing Flickr would be able to do this.

Another technique that is popular with agile approaches are reflection workshops. These are basically opportunities for taking a step back and think about improving the way we work. And if (major) issues are identified in the process then the solution is not only to fix it but to prevent it.

All of these thoughts are not new. Philipp B. Crosby coined the term Zero Defects several decades ago. His book with the title "Quality is Free" is an excellent read. I just finished the sequel "Quality Without Tears" which was published in 1984, long before "Agile" became a hype. When you read the book you will notice that although some terms are different there are a huge amount of commonalities.

Get Quality Without Tears: The Art of Hassle-Free Management

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